Surface non-tidal currents in the approaches to Juan de Fuca strait

1941 ◽  
Vol 5b (4) ◽  
pp. 398-409 ◽  
Author(s):  
John P. Tully
Keyword(s):  
Stream Flow ◽  
Tidal Currents ◽  
Stream Line ◽  
Tidal Circulation ◽  
Land Drainage ◽  
Juan De Fuca ◽  
Wind Driven Currents ◽  
Juan De Fuca Strait

The nature of the surface non-tidal circulation in the sea in the approaches to Juan de Fuca strait, latitude 48°30′N., longitude 125°00′W., is interpreted from stream line diagrams, four of which are reproduced. It is shown that the system represents a balance between a wake stream flow from Juan de Fuca strait, which is directly related to the volume of land drainage, and the independent wind-driven currents, which are due to one of the two prevailing coastwise winds in the area.

Four Pleistocene formations in southwest British Columbia: their implications for patterns of sedimentation of possible Sangamonian to early Wisconsinan age

1983 ◽  
Vol 20 (8) ◽  
pp. 1232-1247 ◽  
Author(s):  
Stephen R. Hicock ◽  
John E. Armstrong
Keyword(s):  
Stream Flow ◽  
Vancouver Island ◽  
Tsuga Heterophylla ◽  
Last Interglacial ◽  
Strait Of Georgia ◽  
Coast Mountains ◽  
Arboreal Pollen ◽  
Juan De Fuca ◽  
Stratigraphic Position ◽  
Juan De Fuca Strait

Semiahmoo and Dashwood drifts were deposited during the penultimate glaciation, and Highbury Sediments and Muir Point Formation during the last interglacial. These sediments are defined and described, and stratotypes are established for them.Based on arboreal pollen assemblages, lithologic similarity, and relative stratigraphic position, Semiahmoo Drift of the Fraser Lowland is tentatively correlated with Dashwood Drift of Vancouver Island. Stone provenance, till fabrics, glaciotectonic structures, cross-bedding, and stone imbrication indicate that regional ice and meltwater flowed out of major fiords in the Coast Mountains and into the ancestral Strait of Georgia during the penultimate glaciation. Ice flowed southeastward against the east coast of Vancouver Island, and down the axis of the strait. Pollen and molluscs in Semiahmoo and Dashwood fossiliferous muds give evidence of transition from glaciomarine to marine conditions at the close of the penultimate glaciation.Highbury Sediments of the Fraser Lowland perhaps correlate with the Muir Point Formation of Vancouver Island, based on lithologic similarity and relative stratigraphic position. Stone provenance and paleocurrent data indicate that stream flow during the last interglacial issued from nearby mountains and onto coastal floodplains that shelved into the ancestral Strait of Georgia and Juan de Fuca Strait. Abundant Pseudotsuga and Tsuga heterophylla pollen indicate that climate during that time was at least as warm as the present.

Tidal Currents in Juan de Fuca Strait

1954 ◽  
Vol 11 (6) ◽  
pp. 799-815 ◽  
Author(s):  
R. H. Herlinveaux
Keyword(s):  
Surface Current ◽  
Geodetic Survey ◽  
Tidal Currents ◽  
Bottom Surface ◽  
Strait Of Georgia ◽  
Juan De Fuca ◽  
Northern Shore ◽  
The Difference ◽  
Flood Current ◽  
Juan De Fuca Strait

Three series of direct current observations taken in Juan de Fuca Strait in 1952 have been analysed. A linear relationship between the difference in sea level on the ocean coast and the Strait of Georgia and tidal currents has been shown. This relation holds from the surface to the lower depths. The current velocities in a cross-section can be predicted at any time. These sections show that the ocean water tends to intrude along the bottom on the flood, expanding upward and favouring the southern shore. The ebbing water is first noticed in the middle of the strait, then it expands down and across favouring the northern shore. The ebb current is stronger at the surface, and the flood current stronger near the bottom. Surface current predictions are shown to be comparable to the U.S. Coast and Geodetic Survey tidal predictions. From this it is reasonable to believe that the predicted tidal currents at the lower depths should also be valid.

Seiche Excitation in Port San Juan, British Columbia

1979 ◽  
Vol 36 (10) ◽  
pp. 1223-1227
Author(s):  
D. D. Lemon ◽  
P. H. LeBlond ◽  
T. R. Osborn
Keyword(s):  
British Columbia ◽  
Water Waves ◽  
Pressure Gauge ◽  
Low Frequency ◽  
San Juan ◽  
External Forcing ◽  
Edge Waves ◽  
Rectangular Basin ◽  
Juan De Fuca ◽  
Juan De Fuca Strait

Seiche motions observed in San Juan Harbour with a bottom-mounted pressure gauge have been Fourier-analyzed and interpreted in terms of a theoretical model of oscillations in a rectangular basin with an exponential depth profile. Two of the observed periods (at 14.6 and 38.5 min) are identified with resonances of the basin; two other significant low frequency peaks (at 21 and 55 min) do not coincide with resonant periods of the basin and must be due to strong external forcing. Higher frequency fluctuations (20–160 s) are attributed to swell and to its subharmonic interactions with edge waves. Key words: water waves, seiches, mathematical model, Juan de Fuca Strait, British Columbia

The tidal circulation and flushing capability of the outer Tay Estuary

1980 ◽  
Vol 78 (3-4) ◽  
pp. s33-s46
Author(s):  
J. A. Charlton
Keyword(s):  
Exchange Rate ◽  
Fresh Water ◽  
Water Discharge ◽  
Hydraulic Model ◽  
Tidal Currents ◽  
Tidal Circulation ◽  
Fresh Water Discharge ◽  
Outer Estuary ◽  
Tay Estuary

SynopsisMeasurements of tidal currents in the outer Tay Estuary, and from the hydraulic model of the estuary, are used to present a tidal atlas of the area and to deduce residual tidal circulation. Additional tests on the model show that the volumetric exchange rate with the sea of the outer estuary can be as high as 58 per cent per tide, but may be lowered to about 35 per cent if multiple tide recirculation is considered. Fresh water discharge into the estuary does not materially affect this exchange rate.

scholarly journals Boundary Layer Forcing of a Semidiurnal, Cross-Channel Seiche

2005 ◽  
Vol 35 (9) ◽  
pp. 1518-1537 ◽  
Author(s):  
Wayne Martin ◽  
Parker MacCready ◽  
Richard Dewey
Keyword(s):  
Boundary Layer ◽  
Numerical Models ◽  
Internal Tide ◽  
Tidal Currents ◽  
Tidal Mixing ◽  
Bottom Boundary Layer ◽  
Salt Balance ◽  
Juan De Fuca ◽  
Similar Mode ◽  
Northern Side

Abstract The outer Strait of Juan de Fuca is a stratified, tidal channel about 100 km long, 20 km wide, and 200 m deep. Tidal currents of O(0.5 m s−1) occur at both diurnal and semidiurnal periods and there is a pronounced spring–neap variation in the stratification due to changes in tidal mixing. Vertical isotherm excursions of O(50 m) have previously been observed along the northern side of the channel that appear to be phase locked to the tidal currents. Analyses of recent ADCP and thermistor chain data confirm the isotherm excursions and find that they are accompanied by distinctive baroclinic structures in the horizontal currents that persist across spring–neap cycles, and from year to year. The authors find that the phase of the semidiurnal signal does not vary along the channel, as would be expected of an along-channel internal tide. Instead, comparison of the semidiurnal measurements with two-dimensional analytical and numerical models indicate that much of the baroclinic structure can be explained as a cross-channel, internal seiche that is locally driven by reversing Ekman forcing in the bottom boundary layer. Near the bottom, the vertical motions are kinematic, resulting primarily from cross-channel flow on the side slopes. In the middepths, the seiche appears to explain part but not all of the vertical motions. The seiche appears to persist and to maintain a similar mode shape across large, O(2), changes in stratification. In Juan de Fuca, it is expected that these motions affect the overall salt balance of the system by enhancing mixing between the upper and lower layers of the estuary.

Offshore Characteristics in the Deep Waters of the Strait of Georgia as Indicated by Bathypelagic Fish

1954 ◽  
Vol 11 (5) ◽  
pp. 501-506
Author(s):  
W. E. Barraclough ◽  
M. Waldichuk
Keyword(s):  
Deep Water ◽  
Fraser River ◽  
Strait Of Georgia ◽  
Deep Waters ◽  
Juan De Fuca ◽  
Bottom Waters ◽  
Chemical Conditions ◽  
Physical And Chemical ◽  
Juan De Fuca Strait ◽  
Inflowing Water

An attempt is made from oceanographical observations to explain the occurrence of certain bathypelagic species of fish which have been captured in the bottom waters of the southern Strait of Georgia. It is noted that there is a considerable seaward surface Sow of water from the Fraser River. The water from intermediate depths over the continental shelf forms the inflowing deep water of Juan de Fuca Strait mixing with the Fraser River water in the turbulent channels of the San Juan Archipelago. This mixture forms the deep inflowing water of southern Strait of Georgia and the outflowing surface water of the Juan de Fuca Strait as shown by salinity distribution and current measurements. The net inward movement of deep water is suggested as an agent of transport or a directive factor for the occurrence of these fish in this region. Physical and chemical conditions of the deep water in the Strait of Georgia are shown to be only slightly different from those found in the intermediate offshore water. It is probable that a combination of factors provides conditions suitable for survival of these species in the deep water of the southern Strait of Georgia.

Late Pleistocene history and geomorphology, southwestern Vancouver Island, British Columbia

1979 ◽  
Vol 16 (9) ◽  
pp. 1645-1657 ◽  
Author(s):  
Neville F. Alley ◽  
Steven C. Chatwin
Keyword(s):  
British Columbia ◽  
Continental Shelf ◽  
Late Pleistocene ◽  
Vancouver Island ◽  
Glacial Lakes ◽  
Small Lakes ◽  
Strait Of Georgia ◽  
Coast Mountains ◽  
Juan De Fuca ◽  
Juan De Fuca Strait

The major Pleistocene deposits and landforms on southwestern Vancouver Island are the result of the Late Wisconsin (Fraser) Glaciation. Cordilleran glaciers formed in the Vancouver Island Mountains and in the Coast Mountains had advanced down Strait of Georgia to southeastern Vancouver Island after 19 000 years BP. The ice split into the Puget and Juan de Fuca lobes, the latter damming small lakes along the southwestern coastal slope of the island. During the maximum of the glaciation (Vashon Stade), southern Vancouver Island lay completely under the cover of an ice-sheet which flowed in a south-southwesterly direction across Juan de Fuca Strait, eventually terminating on the edge of the continental shelf. Deglaciation was by downwasting during which ice thinned into major valleys and the strait. Most upland areas were free of ice down to an elevation of 400 m by before 13 000 years BP. A possible glacier standstill and (or) resurgence occurred along Juan de Fuca Strait and in some interior upland valleys before deglaciation was complete. Glacial lakes occupied major valleys during later stages of deglaciation.

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